Apparatus for ground support

Abstract

An improved apparatus for ground support comprising a tensionable reinforcing member including at least one nut threadably receivable by the tensionable reinforcing member. The nut body comprises a squared portion and a convex hemispherical portion. The nut includes a bore adapted for engagement with the first end threaded portion of the tensionable reinforcing member. The nut also at least one second bore transversing the squared portion of the nut square body portion. The second bore is adapted to accept a shearing element capable to fix the nut in a temporary first operating position on the reinforcing member. The shearing element is a rolled member made from carbon steel. The shearing element is adapted to shear at a consistent and predetermined torqueshear.

Description

CROSS-REFERENCE TO RELATED APPLICATIONS[0001]This application is related to U.S. Pat. No. 6,698,980 entitled “Rock Stabilizing Apparatus and Method”, issued on Mar. 2, 2004 currently pending in the United States Patent and Trademark Office.BACK GROUND OF THE INVENTION[0002]1. Field of the Invention[0003]This invention relates to ground support apparatus used for anchoring unstable rock formations in underground mines. More particularly this invention relates to an improved apparatus for ground support.[0004]2. Background of the Invention[0005]There are a variety of known ground support apparatus and methods for securing unstable rock formations in underground mines. Many of these apparatus and methods rely upon steel reinforcement members placed in pre-drilled holes that are filled with a hardenable resin or cementaceous material. The known ground support apparatus typically comprise a steel reinforcing member as an anchor or length of anchor cable having a nut temporarily fixed at ...

AI Technical Summary

Benefits of technology

"The present invention provides an improved apparatus for ground support that overcomes deficiencies in the prior art. The apparatus includes an elongated reinforcing member with a threaded portion at one end and a reinforcing end adapted to be embedded permanently within a hardenable adhesion material within a drilled hole. The reinforcing member is designed to apply a tensioning force to the rock formation and includes a shearing element that consistently and predictably shears at a predetermined shearing torque. The apparatus also includes a bearing plate that is retained on the reinforcing member and can be advanced to the rock face for transmitting compressive forces to the rock face. The apparatus is designed to fail at torqueshear, ensuring safety during installation. The shearing element is a rolled steel member that is retained within its respective bore to eliminate safety hazards."

Problems solved by technology

These inventions, and others employing the same principals of operation, share common deficiencies:The shearing torque is inconsistent and may be much higher than anticipated thereby creating problems for the operator who must apply much more torque, often manually, to the nut.

This leads to delays in rock anchoring operations and unnecessary expense.

Alternatively, the shearing torque may be too low resulting in the hardenable material not property curing and reducing the strength of the installation.Steel fragments are known to breakaway from the shearing element especially in dome nuts and especially when excessive and unpredictable torque must be applied to fail the shearing element.

These fragments create a safety hazard for the operator and often cause damage to the threads of the reinforcing member or cable.

Thread damage prevents additional bearing plates and nuts from being added to the end of the member as may be required for screening operations.Known shearing elements have a habit of falling out of the assembled ground support apparatus in shipment thereby rendering them useless once they arrive at the work site.

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